The treatment of various liquids by ultrasonic energy is well known. Ultrasonic energy has proven to be an effective means for homogenizing, dispersing, blending, mixing and reducing particles in one or more liquids, as well as for expediting certain chemical reactions. It is also well known that horn resinators can be employed to concentrate ultrasonic energy. U.S. Pat. Nos. 3,715,104 and 3,825,481 employ horn resonators to couple ultrasonic energy to the treated fluid which may comprise foods, medicaments, cosmetics and the like.
FIG. 1 illustrates an example of a conventional flow cell 110 employing a traditional horn 112, which flow cell 110 includes a housing 114 which defines a processing chamber 116. Housing 114 also includes an inlet 118 and an outlet 120 through which a liquid to be treated is passed (indicated by arrows). The end of horn 112 is immersed in the liquid within processing chamber 116 and horn 112 is ultrasonically vibrated to process the liquid.
More specifically, an ultrasonic power supply (not shown) converts typical AC electricity to high frequency electrical energy. This electrical energy is transmitted to a piezoelectric transducer with in a converter 122, where it is changed to mechanical vibrations in the ultrasonic range. The ultrasonic vibrations are intensified by horn 112 and focused at the tip. The ultrasonic activity of horn 112 imparts the vibration energy to the liquid within processing chamber 116 thereby accomplishing the desired result therein. As these processes are well known, more detail is not provided herein.
However, while such a flow cell 110 may provide adequate for homogenizing, dispersing, blending, mixing, reducing particles in and expediting certain chemical reactions in the liquid within processing chamber 116, flow cell 110 does little or nothing to aid in facilitating the flow of materials which typically may stick to and/or clog conduits through which they flow before and after the material is within the processing chamber 116. As such, the material may still stick to and/or clog the conduits leading to and from inlet 118 and outlet 120.
Attempts have been made to design an ultrasonic vibrator specifically configured to aid in facilitating the flow of certain materials. For example, U.S. Pat. No. 5,929,552 is directed to such a device for transporting a small flow rate of powder. The device includes an ultrasonic horn 7A having a hole passing therethrough. Attached at either end of this hole are metallic pipes 14, 15 one of which 14 has attached to it a resilient supply tube 16 which is in turn connected to a supply 1 of the powder to be flowed. A lower end of the horn 7A is rotationally vibrated in an elliptical orbit, the elliptical orbit having an elongated diameter extending in a lateral direction, such that powder passing through the hole and contacting the horn is promoted to flow substantially tangent to the elliptical orbit.
U.S. Pat. No. 5,929,552, however, suffers from a number of disadvantages. Because the patent is concerned with facilitating the flow of powders in a specific way, it is required that the powder actually come in contact with the horn 7A. However, the material which to is be flowed may be chemically incompatible with materials (i.e., typically metals) of which horns are typically made. As such, it would be impossible to employ the device disclosed in U.S. Pat. No. 5,929,552, which specifically requires contact with the horn 7A, in connection with such materials. Moreover, the way in which the device is designed relies on gravity to feed the powder from the supply 1 to the horn 7A, and does nothing to facilitate the flow of the powder from the supply to the horn—because of the precise rotational vibration in an elliptical orbit, flow is only facilitated in the immediate vicinity of the area in which the powder contacts the horn 7A. As such, when materials which typically may stick to and/or dog conduits through which they flow are being used, the material may stick to and/or dog metallic pipe 14 and/or resilient supply tube 16.
FIG. 2 illustrates another attempt to design an ultrasonic vibrator 210 specifically configured to aid in facilitating the flow of certain materials, employing the concept of water coupled ultrasonics. This approach is used when the ultrasonic horn 212 cannot be allowed to touch the materials flowing (indicated by arrows) within a flow tube 214 due to chemical or other incompatibility. Ultrasonic vibrator 210 includes a housing 216 which defines a jacket 218 surrounding flow tube 214 and ultrasonic horn 212, which jacket is filled with water. Ultrasonic energy created by a converter 220 (as discussed more fully above) is transmitted through the water within jacket 218 to flow tube 214 and then to the material to be processed. Water seals 222 are required around flow tube 214 and at the node area of ultrasonic horn 212. Cooling ports 224 and some type of water cooling and/or supply system (not shown) are also required in order to exchange the water within jacket 218, as the water may become excessively heated depending upon the level of ultrasonics required for the application.
This design, however, also suffers from a number of disadvantages. First, because of the indirect nature of the transmission of the ultrasonic energy (i.e., through the water), in order for enough energy to reach the flow tube 214, a high level of ultrasonic energy must be supplied by converter 220. This is an inefficient process, as a great deal of energy may be lost to heating the water. Another disadvantage is the complex (and therefore expensive) nature of the design. As discussed above, ultrasonic vibrator 210 requires water seals 222 at various locations, which seals 222 will have to be replaced from time to time, as well as cooling ports 224 and some type of water cooling and/or supply system (not shown) which are also required in order to exchange the water with in jacket 218. These required elements may greatly increase the initial cost of manufacture as well as the ongoing operational expenses. A further disadvantage is that leaks may develop, thereby allowing the water within jacket 218 to leak, potentially causing damage to converter 220 or other portions of the ultrasonic generation system, as well as other components in connection with which ultrasonic vibrator 210 may be used. Still another disadvantage is that because horn 212 is in direct contact with the water within jacket 218, cavitation may occur when horn 212 is ultrasonically vibrated, which may lead to cavitation erosion of horn 212.
What is desired, therefore, is a flow through ultrasonic system which facilitates the flow of materials which typically may stick to and/or clog conduits through which they flow, which may be used with substantially any type of materials, including those which are chemically or otherwise incompatible with the material of which the horn is formed, which does not require that the material being flowed come in contact with the horn, which is relatively electrically efficient, which is relatively simple in design, which is relatively inexpensive to manufacture and operate, which is not prone to developing potentially damaging leaks, and which is not prone to damage to the horn caused by cavitation erosion.